Aang is using his newly learned firebending skills to form little dancing guys that go "whee", and Zuko is desperately in need of a desk to introduce his forehead to.
Kind of a "what if" scenario, although most of the fandom sees it coming and/or hopes for it that Zuko and Iroh will join the Avatar's gang and teach Aang how to firebend. Well, I certainly do! xD
However, while it would be funny like hell if Zuko was to teach Aang, it would probably not work out. For one, I think Zuko isn't the teacher type, and even if he was, Aang and he are completely different types. Zuko has said before that Aang was a genius like Azula, and Zuko would be irritated to no end if Aang figured out the whole firebending deal in a few days while he himself had to work his whole life.
WHATEVER! I still think it would be fun.
Iroh, Aang and Zuko (c) Mike, Bryan (I blame the fandom for never telling me their last names! xD) and Nickelodeon